Origins of 30 scientific concepts you learned in school

- Discovered by: Seleucus of Seleucia, c. 150 B.C.

Seleucus of Seleucia was a Babylonian astronomer whose life was described by the biographer Plutarch. According to Plutarch, Seleucus was the first to reason out the idea that the sun was the center of the universe. History of Science reports that Seleucus’ finding that the moon causes Earth’s tides was likely related to his examination of the sun.

- Discovered by: Shen Kuo in 1088

The Song dynasty statesman Shen Kuo was the first to decide that true north was different from the magnetic compass north. Shanghai Daily says Shen Kuo studied nature extensively and drew hundreds of sketches before he made this declaration. Along with true north, Shen Kuo was purportedly the first to identify a UFO.

- Discovered by: Theodoric of Freiberg, c. 1310

Although Shen Kuo was reported to have described the rainbow first, it’s Theodoric of Freiberg whose claim survives. History of Science says that Theodoric’s nonscientific education and Dominican monkhood may have overshadowed his devoted interest in the sciences. He understood how rainbows worked, even though he couldn’t formally prove or confirm his understanding.

- Discovered by: Nicolaus Copernicus in 1543

Plutarch claimed that Seleucus of Seleucia was the first to guess the sun was the center of our solar system. Instead, the Stanford Encyclopedia of Philosophy says it was Nicolaus Copernicus. He found the truth as a consequence of his other studies: They just wouldn’t work without the added fact that everything revolved around the sun. By developing and publishing this radical idea, Copernicus helped induce the scientific revolution.

- Discovered by: Galileo in 1638

“What falls faster, a pound of feathers or a pound of lead?” Before Galileo theorized and proved the law of falling bodies, people genuinely believed heavier objects fell faster. According to Nova, Galileo studied falling objects in motion and used ramps to slow their falls so he could observe them.

- Discovered by: Robert Boyle in 1662

Irish-born scientist Robert Boyle was the first to discover that the volume of gas goes down as the pressure on that gas goes up and vice versa. He worked with a colleague to build a pneumatic air pump, which they used to prove this and other findings during their careers. They also discovered facts about combustion and sound transmission over the air.

- Discovered by: Robert Hooke in 1665

The microscope, invented in the 1500s but refined throughout the 1600s, let scientists look at materials at up to 270 times by 1665. That year, Robert Hooke looked at a sample from a cork tree and saw the dead remnants of the cellulose cell wall. He formulated the idea that living things were made of tiny units called cells.

- Discovered by: Antonie van Leeuwenhoek in 1675

Robert Hooke discovered the cell and wrote an influential book called "Micrographia.” Inspired by Hooke, Antonie van Leeuwenhoek built his own microscope and got to work. Where Hooke discovered that “solid” living things were made of cells, van Leeuwenhoek identified living things made of just one cell: bacteria. What he lacked in scientific education, he made up in determination and, frankly, lens-grinding skill.

- Discovered by: Isaac Newton in 1687

The apple drop heard round the world dropped from a tree onto Sir Isaac Newton, who realized that something about the Earth was pulling the apple toward it. He compared this thought to his understanding of how the moon relates to Earth and realized relative size helped to determine gravity. Then he used proof by induction to reason through the law of universal gravity.

- Discovered by: Carl Linnaeus, c. 1735

Carl Linnaeus trained as a doctor in Sweden and the Netherlands, and during his extensive education, he made a system for classifying plants. Over time, he developed this into the modern idea of taxonomy, and he began the “binomial” naming tradition of species. He even theorized, radically, that some new plant species could have emerged after God created the world—strictly by hybrid breeding.

- Discovered by: Benjamin Franklin in 1751

Benjamin Franklin’s legendary kite flying is mostly a legend. In reality, Franklin did fly a kite to harness electric energy from lightning, but ambient energy traveled down the kite string. He’d included a wet hemp string as a conductor and a dry string he could safely hold.

- Discovered by: Jan Ingenhousz in 1778

Dutch physician Jan Ingenhousz piggybacked on the research of another scientist named Joseph Priestley, who discovered that plants release oxygen. Ingenhousz monitored his plants during the day and at night. He noticed that they only released bubbles of oxygen during the day, and he concluded that daylight caused them to release oxygen.

- Discovered by: Antoine Lavoisier in 1789

When elements are combined or even burned, their mass stays the same before and after. We know this now, but conceiving it and believing it required Antoine Lavoisier to understand that some matter was turning into another form, dissipating into the air, and otherwise appearing to disappear. Lavoisier’s discovery led to modern chemistry.

- Discovered by: Georg Ohm in 1827

If you’ve used a hairdryer or heat pad lately, you’ve enjoyed the warm glow of Ohm’s Law. Georg Ohm determined the relationship between voltage, resistance, and current. He discovered and proved that voltage and current were directly proportional, while resistance was the inverse.

- Discovered by: Amedeo Avogadro in 1827

Avogadro’s law says that the same volume of two gases at the same pressure and temperature have the same number of molecules. From this, Avogadro realized you could find the molecular weight for each one by using its density.

- Discovered by: William Thomson, Lord Kelvin in 1848

In 1848, the idea of absolute zero was almost science fiction. Today, the approach to absolute zero is an essential part of many scientific fields, from quantum mechanics to superconductors to cosmology. Kelvin theorized that molecules would stop moving altogether at absolute zero, which he called “infinite cold.”

- Discovered by: Charles Darwin and Alfred Wallace in 1859

Even in this list, Charles Darwin and Alfred Wallace’s discovery of natural selection stands out. Darwin detailed his ideas about the way animals would develop over time into the wildly various species he observed. Even closely related and similar animals had tiny differences that suited where they lived or what they ate. Evolution was much more personally threatening than many other scientific discoveries, and Darwin had a great deal of courage.

- Discovered by: Louis Pasteur in 1861

The father of namesake pasteurization synthesized a bunch of half-right, half-formed ideas from the previous two centuries of science into one cohesive germ theory of disease. From his discovery, people could stop guessing that miasmas or religious punishments were causing the common cold or even the plague. The previous folklore meaning of “contagion” was replaced with real scientific meaning.

- Discovered by: James Clerk Maxwell in 1864

Electromagnetism is what powers the life-sustaining molten core of the Earth, and it touches all of our lives every day down to the molecular level. Scottish scientist James Clerk Maxwell described electromagnetic waves and realized the term applied to the infrared and ultraviolet waves that scientists were already studying. With this one cohesive theory, Maxwell changed or even enabled physics from that point forward.

- Discovered by: Gregor Mendel in 1865

Gregor Mendel experimented with breeding for his entire career, and he was able to conclusively prove that inheritance wasn’t as clear-cut as simply half of one parent and half of the other. By breeding peas, he cataloged dozens of combinations of traits and outcomes that ranged far and wide from any parent plants. He also helped to instill the general idea that a worthwhile experiment had to have many data points to gather all the facts.

- Discovered by: Dmitri Mendeleev in 1869

Avogadro’s pioneering work on relative molecular weight eventually led to atomic weights for all the known elements. Dmitri Mendeleev took these elements and arranged them in order by atomic weight, leaving spaces for elements yet to come. At the time, many scientists had suggested ways to arrange or organize the elements. It was Mendeleev’s choice to arrange the elements “periodically,” with qualities that repeated in a cycle, and that’s made his version the lasting winner.

- Discovered by: Johannes Diderik van der Waals in 1873

The Van der Waals forces describe how many organic gases, liquids, and solids hold themselves together at the molecular level. They especially apply to organic materials, including paraffins and waxes. Without more sophisticated knowledge of subatomic particles, the other forces that bond molecules were more elusive.

- Discovered by: J.J. Thomson in 1897

Not only did J.J. Thomson declare that atoms were made of smaller particles that included electrons—he realized that electrons could travel and do things on their own. His experiments with cathode-ray tubes forecasted much of the development of electronics in the 20th century and beyond. After he voiced his theory, scientists around the world worked together to prove them.

- Discovered by: Alfred Wegener in 1912

Every day, every second, the Earth has brand new ground deep beneath the oceans. This is part of the theory of continental drift, but Alfred Wegener didn’t have the entire thing right when he first devised it in 1912. The missing piece, the idea of plate tectonics, emerged later and joined with the continental drift concept to form one cohesive theory.

- Discovered by: Albert Einstein in 1915

Today, physics is inseparable from the influence of Albert Einstein, even when physicists are working on exceptions to his long-studied theories. But in 1905, when Einstein published the first of his many papers on general relativity, he was a courageous nobody with a wild idea. Einstein outlined how space and time interacted and bent and pulled to create gravity that affected all bodies in space.

- Discovered by: Erwin Schrödinger in 1925

Einstein’s theories opened a watershed in physics, and researchers raced to flush out the full extent of the implications of relativity. The next major finding in the field was Erwin Schrödinger’s equation describing quantum positioning. His work is as important to quantum mechanics as Sir Isaac Newton’s is to classical mechanics.

- Discovered by: Edwin Hubble in 1929

Edwin Hubble, the namesake of the legendary orbiting telescope, voiced the theory that everything in the universe was expanding over time. In fact, it wasn’t just expanding—it was rushing apart depending on how far apart it already was. Hubble’s law served to underpin the idea of the Big Bang, making it a foundational change in scientific thinking.

- Discovered by: Otto Hahn, Lise Meitner, and Fritz Strassmann in 1938

Nuclear fission, which is literally the splitting of a nucleus, was discovered by three scientists on a holiday. Before this, scientists understood the idea of nuclear reactions, and they’d been shooting particles at each other for several years trying to extract information and new elements. But fission was new and unpredictable, sometimes releasing a massive amount of energy. This development eventually led to the nuclear bomb.

- Discovered by: Jonas Salk in 1952

It’s hard to explain today how devastating the poliovirus was before the invention of the polio vaccine. Up to 50,000 new cases occurred each year, mostly in children. This was the crowning achievement of Jonas Salk’s career, but he also worked on vaccines for the flu, and he and his colleagues revolutionized vaccines with killed virus vaccines instead of live virus vaccines.

- Discovered by: James Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin in 1953

As with the gradual development of atomic theory, the study of inheritance and DNA took a long time. The team of researchers who discovered the DNA molecule and its characteristic double-helix shape did so as the keystone to top a century of hard work by many scientists. The double-helix shape brought together all the known portions of information, like the chemical makeup of DNA and how the chemicals pair off.